1. Field of the Invention
The present invention relates to a hydraulic system preferably used for operating a clutch in a hybrid vehicle.
2. Description of the Related Art
A hybrid vehicle is comprised of an electric motor driven by a battery as well as a combustion engine for charging the battery. While the electric motor is steadily coupled with a main driveline to drive the vehicle, the engine is, in a typical construction, not steadily coupled with the main driveline. To selectively couple the engine with the main driveline, a hydraulically operable clutch and an oil pump for driving the clutch are in general provided. Japanese Patent Application Laid-open No. 07-315059 discloses a related art.